There are WAY more ferocious fish that you can buy LEGALLY than a piranha. Piranha’s are over-rated. They get a mean reputation because they breed rather fast, eat all of the food in the small ponds/lakes during the wet season, and then they swim around for weeks literally starving to death. That is the only time they are dangerous as hell. I had 4 whimple piranha’s (the only kind you can buy legally), they were total pussies. I also had a red-bellied pacu. He was a kick ass fish, he ate all of my piranha’s my BIG blue lobster, my sucker fish, chicken fingers, spaghetti, ham, leftover pork chops, whatever the hell I was eating basically.
You need a permit to posess piranha’s simply for the fact that they have the potential to fuck up the local ecology system should you decide to throw 5-10 of them into a small pond. They will eat/breed and spread a little havoc into the area.